1. Field of the Invention
The invention relates to a method of cooling of a space and to an apparatus for carrying out this method.
According to this method a first substance is gasified or vaporized in a first container located in said space, and the gas or vapor thus formed is conducted into a second container located outside said space and containing a second substance generating a lower gas pressure than said first substance at the same temperature, said gas or vapor being caused to be absorbed by said second substance in said second container.
The apparatus for carrying out this method comprises a first container which contains a gasifiable or vaporizable substance and is located in a space to be cooled, at least one second container which is located outside this space, and conduits which comprise a shut off valve and connect said first container with said second container, which contains a second substance, which generates a lower gas pressure than said first substance at the same temperature and has the ability of absorbing gas emitted or generated by said first substance.
The invention is based upon the fact that certain substances absorb gases or vapors chemically, e.g. by binding water of crystallization. During this absorption heat energy is freed in the substance. This heat energy has two sources first chemical energy of the substance and second the heat of vapor absorption which is freed when the chemically active gas or vapor is absorbed by the substance. The substance is enclosed in a container which is connected through a suitable conduit with a second container, which in its turn contains a second substance or liquid, from which the gas is freed, which is absorbed by the substance in the first container. When the gas or vapor is formed in the second container, heat energy (heats of vaporization) is absorbed therefrom and from its surrounding atmosphere, which is accordingly cooled. In the case when the second container contains a substance which contains a chemically bound liquid in its low-energy condition and which releases gas, which is absorbed by the first substance, there is required, in addition to heats of vaporization, release energy for the releasing of the chemically bound liquid.
2. Description of the Prior Art
A process and an apparatus which is based upon this principle is disclosed in the U.S. Pat. No. 3,642,059 to Greiner and comprises two vessels interconnected by a conduit, the first containing a vaporizable liquid, e.g. water, and the second containing vapor-absorptive chemical, e.g. Na.sub.2 O. Liquid is vaporized from the first vessel and the vapors are drawn by the vapor-absorptive chemical through the conduit to the second vessel where they are absorbed and condensed. The consequence hereof is that the first vessel is cooled through heats of vaporization and that the second vessel is heated through heats of vapor absorption.
As far as we are aware no apparatus according to this patent has been built. The main reason for that probably resides in the fact that the inventor has neglected to take the importance of the residual gases in the apparatus into consideration. The partial pressure of these gases has to be much lower than the pressure of water vapor at the actual equilibrium and not "lower than the atmospheric". This statement means that the supply of liquid (water) to the Greiner apparatus continuously introduces gases dissolved in the water, and these gases arrest the process.
Furthermore, none of the chemicals proposed by Greiner has the majority of such physical and chemical properties as are essential for an operative apparatus. The most important of these properties are (1) high exchange of energy, counted per unit of weight and volume of substance at one and the same phase transition; (2) unchanged (solid) state of aggregation in charged as well as in discharged condition; (3) minimal change of volume at the absorption of gas or vapor; (4) large maintained active surface of reaction throughout the whole process; and (5) unlimited number of charging and discharging (cooling) operations in one and the same container.